Which of the following gases is the best choice for inflating a balloon that must remain inflated for a long period of time?

The higher the molar mass the more trouble th gas has of getting out of the balloon. The smaller the molar mass.......the easier it is to escape.

So it's between Argon and Neon right?

and thank you for helping me

Why between Ar and Ne? Unless you are just eliminating O and H to concentrate on the other two. On my periodic table, I have the following:
Ar = about 40
Ne = about 20
O = about 32
H = about 2

all I know is that Nitrogen and Helium are the one; but these I do not know

It is A. Argon
Because it is the heaviest gas so we know it will not be seeping through the balloons walls if it is not hitting them as much as the lighter gases are.
Helium is the worst option for length in time because how light it is, that's why oxygen inflated balloons last longer.